Marlborough College assesses 13+ candidates through three things rather than one: the ISEB Pre-Test, a reference from the current school, and an assessment day at the College. No single element decides a place, and the assessment day in particular is more rounded than a written exam. Knowing what each part involves, and what it rewards, is the difference between preparation that works and preparation that simply tires a child out. This guide explains the process and how to prepare.
- Three parts
- ISEB Pre-Test, school reference, assessment day
- Pre-test
- ISEB Common Pre-Test, September to December of Year 6
- Pre-test subjects
- English, Maths, Verbal Reasoning, Non-Verbal Reasoning
- Assessment day
- Writing task, informal group activities, interview
- Decision
- Based on all three elements together
The three-part process
Marlborough is clear that it assesses 13+ candidates through three elements: the ISEB Pre-Test, a reference from the child's current school, and an assessment day at the College. The school weighs all three together, which is worth understanding from the start. A child who tests well but does not come across as a good fit on the assessment day, or whose reference raises concerns, is not assessed on the pre-test alone. Equally, a child who is slightly below the very top on paper but shines in person and comes warmly recommended can do very well. The process is designed to see the whole child.
The ISEB Common Pre-Test
The first stage is the ISEB Common Pre-Test, taken at your child's current school between September and December of Year 6, or Year 7 for the smaller later cohort. It is the same standardised, online test that many leading senior schools use as an early screen, so children usually sit it once and have the result shared with several schools. Because it is age-standardised, it measures your child against others of exactly the same age in months, so a summer-born child is not disadvantaged against an older classmate. Our dedicated guide to the ISEB Common Pre-Test covers it in full. The summary below focuses on what matters for Marlborough.
Pre-test format and timings
The pre-test is taken on a computer, is adaptive, and covers four sections with the approximate timings below.
| Section | Time | What it tests |
|---|---|---|
| English | 40 min | Comprehension, grammar, spelling and vocabulary |
| Mathematics | 40 min | Curriculum maths and applied problem-solving |
| Verbal Reasoning | 25 min | Logic and reasoning with words |
| Non-Verbal Reasoning | 30 min | Pattern, sequence and spatial reasoning |
| Total | ~2h 15m | Usually taken in one sitting at the current school |
The assessment day
Children who do well at pre-test are invited to an assessment day at Marlborough, and this is where the College forms its real view. Marlborough describes the day as deliberately low-pressure rather than a high-stakes exam. It includes a short writing task, informal group activities with other candidates, and an interview, which is typically conducted by a Housemaster or Housemistress. The College is looking at how a child engages: how they present themselves in discussion, how they work alongside others in the group activities, and whether they seem suited to a full-boarding community where everyone lives on site. The writing task gives a sense of how a child expresses themselves on paper without the pressure of a formal exam. Taken together with the pre-test and the reference, the day gives Marlborough a rounded picture.
How to prepare
Marlborough is looking for genuine ability and a child who will thrive in its community, not one who has been coached until the spark has gone. The foundation is secure maths and English built early, which matters far more than last-minute drilling. Reasoning improves with familiarity, so short, regular practice on verbal and non-verbal reasoning is more effective than occasional long sessions. Wide reading helps in the English paper, the writing task and the interview alike. Because the pre-test is timed, adaptive and on-screen, some online practice under realistic conditions is worth doing so the format holds no surprises. For the assessment day, the most useful preparation is the kind that builds confidence in talking about ideas and working with other children, since the interview and group activities reward exactly those qualities. A child who is used to discussing books and ideas at home, and who has plenty of experience working in groups at school, is already most of the way there.
Give your child the best possible shot at the Marlborough assessment
Our tutors prepare children specifically for the ISEB Pre-Test and the Marlborough assessment day, with an approach that is targeted, calm and tailored to your child. Book a free diagnostic to see where they stand.
Book a free diagnosticWhat to avoid
The first thing to avoid is over-coaching. Marlborough's staff are experienced at spotting a heavily drilled child, and the relaxed assessment day is designed to see past a rehearsed performance. The second is treating the pre-test as the whole assessment. It is one of three elements, and a child who prepares only for the test can be caught short by the writing task, the group activities and the interview. The third is neglecting reasoning, which families often treat as an afterthought even though it makes up half of the pre-test.
